Secondary Succession in the Tropical Lowland Rainforest Reduced the Stochasticity of Soil Bacterial Communities through the Stability of Plant Communities

Xuan Hu,Lianghua Qi,Zean Shang,Qi Shu,Wen Guo

doi:10.3390/f13020348

Abstract

The effects of natural succession on plant and soil bacterial communities were previously established, but changes in plant and soil bacterial communities and their response to soil properties are not well characterized in different stages of secondary forest succession, especially in tropical regions with endemic plant species. We investigated the dynamics of plant communities, soil properties and the structure of soil bacterial communities at sites representing 33 (early successional stage), 60 (early-mid successional stage) and 73 (mid successional stage) years of secondary succession in the tropical lowland rainforest of Hainan, China, by using16S rRNA high-throughput sequencing. From the perspective of plant composition, the number of families, genera and species were increasing along with the progress of succession. Additionally, the changes in the ranking of important values along with the progress of the forest succession were consistent with the niche width calculated by the previous stage of the plant community. The results of niche overlap, Pearson’s correlation and Spearman’s rank correlation coefficients and significance indicated that in the early stage of succession, tree species did not fully utilize environmental resources. Then, as time went by, the number of negative correlations of plants in the early-mid stage was more than that in the mid stage of succession. Significant differences were found in the species richness of soil microorganisms among the three successional stages. Nutrient contents in early successional stage rainforests were less abundant than in early-mid and mid forest soils. The influence of soil nutrient concentration, particularly N and P content, on soil bacterial composition at the phylum level was larger in the early-mid stage than in the mid stage. The stochasticity of the soil bacterial community at the early successional stage of the rainforest was significantly higher than that at mid stage. Overall, as the diversity of plant communities increased, the competition decreased, the soil nutrient content changed and the stochasticity of soil bacterial communities decreased as a result of forest succession.

Highlights

The present study investigated the dynamics of plant communities, soil properties and the structure of soil bacterial communities at sites representing 33, 60 and 73 years of secondary succession in the tropical lowland rainforest of Hainan, China, by using16S
Except for the total phosphorus (TP) content, the content of all other nutrients was significantly lower in the early stage than in the early-mid and mid stages
There was no significant difference in the pH value of the tropical rain forest soils among the three different successional stages, all showing an acidic state

Summary

Introduction

Tropical forests are one of the most important biomes worldwide. With only 12% of the global land area, they act as both global warehouses of biodiversity Tropical forests dominate terrestrial C dynamics, contributing almost 70% of the global gross forest C sink for the time period of 1990–2007 [2]. Less than 50% of the world’s tropical forests remain standing today, with much of the remaining forest cover seriously affected by human activities, such as logging, fires, fragmentation, mining, hunting, and conversion to pastures. The degradation of tropical rain forests may have strong negative consequences for biodiversity, climate normalization, and the well-being of rural and urban populations [3,4]

Objectives

Methods

Results

Discussion

Conclusion